$PIMCO Global Stocksplus & Income Fund (PGP.US)$ PGP's manag...

PGP's managers have done a terrific job earning an annualized 15% per annum on this PIMCO fund's net assets over the past 10 years.

But that's little consolation to investors who've lost their shirts because they bought it four or five years ago at nosebleed-level premiums of 60 and 70%.

In other words, PGP is a "poster child" for how premiums and discounts really matter to overall total return.

And the best portfolio managers in the business can't save you if you pay too far above what a fund is really worth.